Systematic Uncertainties and Cross-Checks for the NOvA Joint ${\nu }_{\mu }$+${\nu }_e$ Analysis

The physics goals of NOvA are the constraints of neutrino oscillation parameters such as the octant of ${\theta }_{23}$, ${\delta }_{\mathrm{C}\mathrm{P}}$, and the neutrino mass hierarchy via a joint fit to ${\nu }_{\mu }$ and ${\nu }_e$ oscillation spectrum. We do this by propagating ${\nu }_{\mu }$ from the world’s most intense neutrino beam at Fermilab, over a baseline of 810 km to northern Minnesota, USA, and measure the ${\nu }_{\mu }$ to ${\nu }_e$ oscillation probability. NOvA announced its latest oscillation results, based on 8.85$\times {10}^{20}$ (6.9$\times {10}^{20}$) protons on target neutrino (antineutrino) data. Preliminary results for the allowed values of oscillation parameters are: $\Delta m^2_{32}=2.51^{+0.12}{-0.08}\times 10^{-3} $\mathrm{e}\mathrm{V}$^2$,$$\mathrm{s}\mathrm{i}\mathrm{n}$^2\theta{23} = 0.58 \pm 0.03$(upperoctant),and$\delta_{\rm{CP}}=0.17\pi$ with preference to the normal hierarchy. Reliable constraints on these oscillation parameters require a rigorous treatment of systematic uncertainties and thorough cross-checks. In this paper, we present an overview of the treatment of systematic uncertainties as well as cross-checks using muon removed simulations and cosmic muon bremsstrahlung showers.